After a death, there are just 5 northern white rhinos left

In this photo taken Monday, Dec. 1, 2014, female northern white rhino Najin stands in her pen where she is being kept for observation at the Ol Pejeta Conservancy in Kenya. (AP Photo/Ben Curtis)

The number of northern white rhinos left on the planet can now be counted on one hand. Angalifu, one of the last six members of the species remaining and one of only two males, died yesterday at the San Diego Zoo Safari Park, apparently of old age, the San Diego Union-Tribune reports.